Image Processing Device, Imaging Device, Image Processing Method, Imaging Method, And Image Processing Program

ABSTRACT

An image processing device comprising
         a synchronization unit ( 25 ) for generating a luminance (Y′) from the sum of pixel signals R, Gr, Gb, B, for subtracting the R pixel signal and the B pixel signal from the sum of the Gr pixel signal and Gb pixel signal so as to generate a first color difference (C 1 ), and for calculating a difference between the R pixel signal and the B pixel signal to generate a second color difference (C 2 ),   a pseudo-color suppression unit ( 31 ) for performing pseudo-color suppression of the first color difference (C 1 ) and/or the second color difference (C 2 ),   a color space conversion unit ( 37 ) for converting the luminance Y′, the first color difference (C 1 ), the second color difference (C 2 ), into a predetermined color space to generate YUV color information.

An image processing device, an imaging device, an image processingmethod, an imaging method, and an image processing program.

FIELD OF INVENTION

The present invention relates to a technology for an image processingdevice and an imaging device, equipped with a CCD having a RGB threeprimary colors Bayer color filter, with multiple photo-electricconversion elements (pixels) laid out in 2-dimensional manner, whichprovides especially good resolution, low pseudo-color and improved imagequality.

BACKGROUND OF THE INVENTION

In traditional digital cameras, an image processing device and an imageprocessing method is known having an imaging system wherein thephotographed image goes through the lens, forms an image on the CCDwhere the subject image is photo electrically converted and an imagesignal is generated.

Next, with a single-chip CCD, an image processing device and an imageprocessing method are known that in addition to a matrix having aplurality of photo electric conversion elements are further equippedwith a color filter before it and the image data is generated aftersignal processing of each color pixel signal output through the colorfilter.

Also, in the image processing device, the color filter of thesingle-chip CCD is equipped with an R (red), G (green) and B (blue)3-color Bayer array matrix for each of the photo electric conversionelements. A luminance signal and color difference signal for each unitis generated from the output signal (1 unit=1 R pixel, 2 G pixels, 1 Bpixel for a total of 4 pixels) of this CCD, and a color image signalhaving all the color image pixels is generated from these signals (foran example see Patent Reference 1).

For example, in an image processing device equipped with theaforementioned single-chip imaging device, the R, Gr, Gb, B colorsignals are loaded after going through the Bayer array color filterequipped CCD (Charge Coupled Device) and then 4 pixels each of R, Gr, Gband B are sampled and an image signal having the center pixel of thefour pixels signal is generated.

In more detail, although each pixel of a single-chip CCD contains onlythe color information of a single color all the red (R), blue (B) andgreen (G) values for each pixel is necessary to display a color image.Due to this, in imaging processing that uses a single-chip CCD, aso-called demosaic process is performed based on the color mosaic imagehaving only an R, G, or B components. The demosaic process is a processthat generates a color image with each pixel having all the RGBconstituents with the use of interpolation calculation on the lackingcolor luminance information gathered from the surrounding pixels of thecorresponding color mosaic image pixels (which is called interpolationprocessing).

However, in image processing that uses a single-chip CCD, if onlyinterpolation is performed then there is a danger of pseudo-colorgeneration or loss of image resolution.

For example, as the sampling frequency of the R signal and B signal isonly ½ that of the G signal, any sampling greater than fs/2 (Nyquistfrequency) will be cut-off due to the sampling theorem. Also, the Rsignal and B single phases will, at fs/2, be out of alignment with eachother.

Therefore, due to the aforementioned cut-off phase difference there is aproblem of the pseudo-color (for example, formation of a stripe patternnot in the original photographed object) occurrence on both surfaces.Therefore, in order to prevent pseudo-color, there is a method in whichan optical filter having a cut-off frequency of approximately fs/2 isplaced between the lens and the CCD so that any light radiation greaterthan fs/2 is cut-off (for example, see Patent Reference 2).

Also, for the aforementioned color image processing device, there is amethod of pseudo-color suppression in which, focusing on suppression ofpseudo-color occurring at the image edge, the difference of theplurality of nearby pixel signals is compared and if this differenceexceeds a pre-set specified value (threshold value) the pixel signal issuppressed, thus achieving pseudo-color suppression (for example, seePatent Reference 3).

-   Patent Reference 1: Tokukai 2000-287211 Bulletin-   Patent Reference 2: Tokukai Hei 7-7733 Bulletin-   Patent Reference 3: Tokukai Hei 11-308625 Bulletin

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, in the traditional manner, if an optical filter having acut-off frequency of about fs/2 is placed between the lens and CCD, inaddition to pseudo-color removal there was also the fear that correctsignal constituents would also be cut off and image qualitydeteriorates.

Also, as in Patent Reference 3, with the method of suppressingpseudo-color by comparison of the difference of the plurality of nearbypixel signals near the edge, with the difference being within apre-determined specified limit, there is the danger that color stripesthat are not pseudo-color are mistakenly reduced resulting in a loss ofcolor saturation.

Consequently, the present invention provides, with suppression ofpseudo-color and no loss of resolution, an image processing device andan imaging device, an image processing method and an imaging method, andan image processing program for the purpose of obtaining a high-qualitycolor image.

Means for Solving the Problems

In order to achieve the above stated purpose, an image processing deviceaccording to Claim 1 of the invention wherein: said device generates acolor image constituted of pixels each holding a plurality of colorinformation from a color mosaic image formed from the R (red), Gr (greenlocated next to R in the above noted one-way direction), Gb (greenlocated next to B in the above noted one-way direction) and B (blue)output of a CCD having a Bayer color filter array. Wherein, at the pixellocation in the above mentioned color image, a synchronization methodfor the above mentioned R , Gr, Gb and B as a single unit, a luminanceis generated from the sum of the above mentioned R, Gr, Gb and B pixelsignal, and by subtracting the above mentioned R pixel signal and Bpixel signal from the sum of the abovementioned Gr pixel signal and Gbpixel signal a 1^(st) color difference is generated and, at the sametime, the difference between the above mentioned R pixel signal and Bpixel signal is calculated to generate a 2^(nd) color difference, apseudo-color suppression method in which at least the pseudo-color ofeither the 1^(st) color difference or 2^(nd) color difference issuppressed, and the color space conversion method which generates theabove mentioned color information from the determined color spaceconversion after the above mentioned luminance and pseudo-colorsuppression method of the 1^(st) and 2^(nd) color difference.

According to Claim 1 of the invention, providing pseudo-colorsuppression without loss of resolution and high quality image,especially the effective suppression of pseudo-color from mistakendetection of high frequency constituents of luminance as a colordifference through: at the pixel location in the above mentioned colorimage, a synchronization method for the above mentioned R, Gr, Gb and Bas a single unit, a luminance is generated from the sum of the abovementioned R, Gr, Gb and B pixel signal, and by subtracting the abovementioned R pixel signal and B pixel signal from the sum of the abovementioned Gr pixel signal and Gb pixel signal a 1^(st) color differenceis generated and, at the same time, the difference between the abovementioned R pixel signal and B pixel signal is calculated to generate a2^(nd) color difference, a pseudo-color suppression method in which atleast the pseudo-color of either the 1^(st) color difference or 2^(nd)color difference is suppressed, and the color space conversion methodwhich generates the above mentioned color information from thedetermined color space conversion after the above mentioned luminanceand pseudo-color suppression method of the 1^(st) and 2^(nd) colordifference.

This application's inventor has identified that, in the color mosaicimage as output from the CCD having a Bayer array color filter, the1^(st) color difference pseudo-color expression is more in the obliquedirection while the 2^(nd) color difference pseudo-color expression ismore in the horizontal/vertical directions. Therefore, by generating the1^(st) color difference and 2^(nd) color difference from the mosaicimage and reducing this to a specified quantitative amount, a highquality color image can be obtained.

An image processing device according to Claim 1 wherein, as in theinvention of Claim 2, as the above mentioned pseudo-color suppressioninformation, a pseudo-color generation method from the generation of atleast one parameter of the 1^(st) parameter or 2^(nd) parameterexpressing the high frequency component amount of the luminancediffering directions for which the pseudo-color signal in the 1^(st)color difference and 2^(nd) color difference are included can besuppressed well and precisely in accordance with these parameters.

An image processing device according to Claim 2 wherein, as in theinvention of Claim 3, the above mentioned 2^(nd) parameter is theparameter expressing the difference between the above mentioned Gr pixelsignal and to Gb pixel signal and from this, in accordance with the Grto Gb difference pseudo-color amount is calculated and the pseudo-colorcan be suppressed. In other words, when an image, including a stripepattern having an fs/2 cyclic luminance in either the vertical orhorizontal direction, is formed on a Bayer array CCD, the luminance ofthe image formed on the R pixels and/or B pixels is different andpseudo-color occurs. At this time, in the same manner the luminance ofthe Gr pixels and Gb pixels differs so this Gr to Gb difference can beused as the 2^(nd) parameter of the pseudo-color suppressioninformation.

An image processing device according to Claim 2 wherein, as in the Claim4 invention, the above mentioned pseudo-color suppression methodsuppresses the above mentioned 1^(st) color difference in accordancewith the above mentioned 1^(st) parameter and suppresses the abovementioned 2^(nd) color difference in accordance with the 2^(nd)parameter and the pseudo-color in the 1^(st) color difference and the2^(nd) color difference can be suppressed.

An image processing device according to any of the Claim 1 or Claim 4wherein, as in the Claim 5 invention with a low frequency pass filter,the 1^(st) color difference and 2^(nd) color difference output from theabove mentioned pseudo-color suppression method goes through the lowfrequency pass filter to remove high frequency noise so that colordifference noise in the color image can be reduced resulting in a higherquality color image being generated.

An image processing device according to Claim 1 wherein, as in the Claim6 invention with the above mentioned pseudo-color suppression methodbeing a low frequency pass filter to remove the high frequency componentof the 1^(st) color difference and the 2^(nd) color difference, the1^(st) color difference and 2^(nd) color difference phase mismatch canbe suppressed resulting in a higher quality color image being obtained.

Next, according to the invention of Claim 7, an imaging device equippedwith an imaging optics system to introduce the subject image to theabove mentioned CCD and an image processing device to generate, inaccordance with the mosaic image signal output from the above mentionedCCD, a color image having a plurality of color information of each pixelwherein the above mentioned image processing device is that of eitherClaim 1 or Claim 6.

According to the imaging device of Claim 7, as it is equipped with animage processing device of either Claim 1 or Claim 6, pseudo-color canbe suppressed without degrading the resolution and a high quality colorimage obtained, especially effective is the suppression of pseudo-colorgenerated from mistaken detection of the high frequency component ofluminance as color difference.

Also, the imaging device according to Claim 7, as in the invention asnoted in Claim 8, is comprised so that on the incident light pathforming the object image on the above mentioned CCD, on the abovementioned color image pixel array, equipped with an optical low passfilter for oblique direction luminance high frequency suppression withthe cutoff of the aforementioned optical low pass filter beingassociated with the above mentioned color mosaic image pixel arraydirection, forming a quadrangle having a 45° angle with the origin pointas its center on the above mentioned color mosaic image frequency space,with the inside of this quadrangle being the transmission band.Therefore, from this composition, the luminance high frequency in thepixel array oblique direction that appears in the 1^(st) colordifference can be effectively suppressed and interdependently of thepseudo-color suppression method a further level of effectivepseudo-color suppression can be accomplished.

Next, according to the invention of Claim 9, an imaging processingmethod wherein: there is an image processing method that generates acolor image having all the plurality of color information for each pixelfrom a color mosaic image of the output from a Bayer array CCD with R(red) Gr (the green next to the above mentioned R in one direction ofthe pixel array), Gb is (the green next to the B in the above mentionedone direction) and B (blue) pixels, and at the pixel position in theabove mentioned color image with the above mentioned R, Gr, Gb and Bpixels as a single unified unit plus there is a luminance (Y) generationstep from the sum of the above mentioned R, Gr Gb and B pixel signalsand a 1^(st) color difference step from subtracting the above mentionedR pixel signal and B pixel signal from the sum of the above mentioned Grpixel signal and Gb pixel signal and a 2^(nd) color differencegeneration step from the calculation of the difference between the abovementioned R pixel signal and B pixel signal and a pseudo-colorsuppression step using the above mentioned luminance information and atleast one of the 1^(st) color difference and 2^(nd) color differencewith the 1^(st) color difference and 2^(nd) color difference from theoutput of the above mentioned pseudo-color suppression step beingconverted to a specified color space so as to generate the abovementioned color information.

In the image processing method according to Claim 9, R, Gr, Gb and B areunified into a single unit by correlating them with pixel positions in acolor image, there is a luminance (Y′) generation step with the sum ofthe pixel signals R, Gr, Gb, B, a 1^(st) color difference generationstep by subtracting the R pixel signal and the B pixel signal from thesum of the Gr pixel signal and Gb pixel signal, a 2^(nd) colordifference generation step by calculation of the difference between theR pixel signal and the B pixel signal, a pseudo-color suppression stepof at least one of either the 1^(st) color difference or the 2^(nd)color difference pseudo-color, a color space conversion step forgeneration of the above mentioned color information after conversion ofthe luminance and pseudo-color suppressed 1^(st) color difference,2^(nd) color difference into a determined color space and, in the samemanner as with the invention of Claim 1, providing pseudo-colorsuppression without loss of resolution and enabling a high quality colorimage, especially with the effective suppression of pseudo-color fromthe CCD output pixel signal.

The image processing method according to Claim 9, as in the invention asnoted in Claim 10, as the pseudo-color suppression method is comprisedso as to use a pseudo-color information generation step that generatesat least one of either the 1^(st) parameter or 2^(nd) parameter, whichexpress the high frequency component of the luminance differingdirections, as the above mentioned pseudo-color information. And, as inthe invention noted in Claim 2, the pseudo-color signal componentincluded in the 1^(st) color difference and the 2^(nd) color differencecan be well and precisely suppressed in accordance with theseparameters.

The image processing method according to Claim 10, as in the inventionof Claim 11, as the above mentioned 2^(nd) parameter is the parameterexpressing the difference of the above mentioned Gr pixel signal and Gbpixel signal pseudo-color can be suppressed, in the same manner as theinvention of Claim 3, by calculation of the pseudo-color amount inaccordance with the Gr and Gb difference.

The image processing method according to Claim 10, as in the inventionof Claim 12, in the above mentioned pseudo-color suppression step, asthe 1^(st) color difference is suppressed in accordance with the 1^(st)parameter and the 2^(nd) color difference is suppressed in accordancewith the 2^(nd) parameter, the pseudo-color in the 1^(st) colordifference and 2^(nd) color difference can be suppressed, just as in theClaim 4 invention.

The image processing method according to either Claim 9 or Claim 12, inthe same manner as the invention of Claim 13, uses a low frequency topass filter to remove the high frequency component of the abovementioned pseudo-color suppression step's 1^(st) color difference and2^(nd) color difference output so, in the same manner as noted in theinvention of Claim 5, the color difference noise in the color image canbe decreased resulting in the generation of a further enhanced highquality image.

The image processing method according to Claim 9, in the same manner asthe invention noted in Claim 14, as a low frequency pass filter removesthe high frequency component of the above mentioned pseudo-colorsuppression step's 1^(st) color difference and 2^(nd) color differenceso, in the same manner as the invention noted in Claim 6, the 1^(st)color difference and 2^(nd) color difference phase mismatch can besuppressed and a high quality color image obtained.

Next, the invention according to Claim 15, is an imaging method wherein:imaging processing is performed using an imaging optics system tointroduce the subject image to the above mentioned CCD and generating acolor image having a plurality of color information for each pixel inaccordance with the color mosaic image signal output from the abovementioned CCD, with the above mentioned image processing method beingthat of either Claim 9 or Claim 14.

According to the imaging method as noted in Claim 15, as the imageprocessing method is either that of Claim 9 or Claim 14 pseudo-color canbe suppressed without the loss of resolution, in the same manner as theinvention noted in Claim 7, and a high quality color image obtained.Especially, the effective suppression of pseudo-color arising frommistaken detection of high frequency constituents of luminance as acolor difference can be achieved.

As the imaging method noted in Claim 15, as in the invention of Claim16, is comprised so that on the incident light path forming the objectimage on the above mentioned CCD, on the above mentioned color imagepixel array, there is an optical low pass filter for oblique directionluminance high frequency suppression with the cutoff of theaforementioned optical low pass filter being associated with the abovementioned color mosaic image pixel array direction, forming a quadranglehaving a 45° angle with the origin point as its center on the abovementioned color mosaic image frequency space, with the inside of thisquadrangle being the transmission band. Therefore, in the same manner asin the invention noted in Claim 8, the luminance high frequency in thepixel array oblique direction that appears in the 1^(st) colordifference pseudo-color can be effectively suppressed andinterdependently of the pseudo-color suppression method a further levelof effective pseudo-color suppression can be accomplished.

Next, according to the invention of Claim 17, an image processingprogram that generates a color image having all the plurality of colorinformation for each pixel from a color mosaic image of the output froma Bayer array CCD with R (red) Gr (the green next to the above mentionedR in one direction of the pixel array), Gb (the green next to the B inthe above mentioned one direction) and B (blue) pixels, and at the pixelposition in the above mentioned color image with the above mentioned R,Gr, Gb and B pixels as a single unified unit, there is a luminance (Y)generation step from the sum of the above mentioned R, Gr Gb and B pixelsignals and a 1^(st) color difference step from subtracting the abovementioned R pixel signal and B pixel signal from the sum of the abovementioned Gr pixel signal and Gb pixel signal and a 2^(nd) colordifference generation step from the calculation of the differencebetween the above mentioned R pixel signal and B pixel signal and apseudo-color suppression step using at least one of the above mentionedluminance information or 1^(st) color difference and 2^(nd) colordifference with the 1^(st) color difference and 2^(n)d color differencefrom the output of the above mentioned pseudo-color suppression stepbeing converted to a specified color space so as to generate the abovementioned color information being computer executed.

According to the image processing program of Claim 17, wherein: at thepixel position of the color image there is a luminance (Y) generationstep, with R, Gr, Gb and B as a single unit, from the sum of the pixelsignals R, Gr, Gb and B, and a 1^(st) color difference generation stepfrom subtracting the above mentioned R pixel signal and B pixel signalfrom the sum of the above mentioned Gr pixel signal and Gb pixel signaland a 2^(nd) color difference generation step from the calculation ofthe difference between the above mentioned R pixel signal and B pixelsignal and a pseudo-color suppression step using at least one of theabove mentioned luminance information or 1^(st) color difference and2^(nd) color difference with the luminance 1^(st) color difference and2^(nd) color difference from the output of the above mentionedpseudo-color suppression step being converted to a specified color spaceso as to generate the above mentioned color information executed bycomputer so that, in the same manner as the invention noted in Claim 1,pseudo-color suppression without loss of resolution and high qualityimage can be achieved, especially the effective suppression ofpseudo-color from mistaken detection of high frequency constituents ofluminance as a color difference is possible.

The image processing program as noted in Claim 17, as in the inventionas noted in Claim 18, as the above mentioned pseudo-color information,there is a computer executed pseudo-color information generation stepusing at least the generation of one of the 1^(st) or 2^(nd) parameterswhich express the luminance differing directions high frequencyconstituent amount so that, in the same manner as the invention of Claim2, the pseudo-color signal component included in the 1^(st) colordifference and the 2^(nd) color difference can be well and preciselysuppressed in accordance with these parameters.

The image processing program as noted in Claim 18, as in the inventionas noted in Claim 19, as the above mentioned 2^(nd) parameter is theparameter expressing the difference of the above mentioned Gr pixelsignal and Gb pixel signal pseudo-color can be suppressed, in the samemanner as the invention of Claim 3, by calculation of the pseudo-coloramount.

The image processing program as noted in Claim 18, as in the inventionas noted in Claim 20, in the above mentioned pseudo-color suppressionstep, the above mentioned 1^(st) color difference pseudo-color issuppressed in accordance with the above mentioned 1^(st) parameter andthe above mentioned 2^(nd) color difference pseudo-color is suppressedin accordance with the above mentioned 2^(nd) parameter by computerexecution and, in the same manner as the invention noted in Claim 4, thepseudo-color included in the 1^(st) color difference and 2^(nd) colordifference can be suppressed.

The image processing program as noted in either Claim 17 or Claim 20, asin the invention as noted in Claim 21, the 1^(st) color difference and2^(nd) color difference from the pseudo-color suppression step goesthrough the low-frequency pass filter to remove the high frequencycomponent by computer execution and, in the same manner as the notedinvention of Claim 5, the color difference noise in the color image canbe decreased resulting in the generation of a further enhanced highquality image.

The image processing program as noted in Claim 17, as in the inventionas noted in Claim 22, having the above mentioned pseudo-colorsuppression step wherein a low frequency pass filter is used to removethe high frequency component of the above mentioned 1^(st) colordifference and the 2^(nd) color difference, executed by computer, and inthe same manner as the invention noted in Claim 6, the phase mismatchbetween the 1^(st) color difference and 2^(nd) color difference can besuppressed resulting in a higher quality color image being obtained.

Advantageous Effect of the Invention

An image processing device and an imaging device, an image processingmethod and an imaging method, and an image processing program of thisinvention can suppress pseudo-color without degrading the resolution andprovide a high quality color image. With the use of the invention, R,Gr, Gb and B are unified into a single unit by correlating them withpixel positions in a color image, generating a luminance (Y′) from thesum of the pixel signals R, Gr, Gb, B, subtracts the R pixel signal andthe B pixel signal from the sum of the Gr pixel signal and Gb pixelsignal so as to generate a 1^(st) color difference, and calculates adifference between the

R pixel signal and the B pixel signal to generate a 2^(nd) colordifference. Next, pseudo-color suppression of both the 1^(st) colordifference and 2^(nd) color difference is performed. Subsequently, eachof the luminance Y′, the 1^(st) color difference, and the 2^(nd) colordifference is converted into a predetermined color space to generatecolor information.

In the present invention, as the pseudo-color suppression information,through generation of the 1^(st) and 2^(nd) parameters, which expressthe luminance high frequency component amount, the pseudo-color signalcomponent, in accordance with the 1^(st) parameter and 2^(nd) parameter,in the 1^(st) color difference and 2^(nd) color difference can be welland precisely suppressed.

In the present invention, as the 2^(nd) parameter is the parameterexpressing the difference between the Gr pixel signal and the Gb pixelsignal so the pseudo-color amount is calculated in accordance with theGr to Gb difference and pseudo-color can be suppressed.

In the present invention, as the pseudo-color suppression method iscomprised so that the 1^(st) color difference is suppressed inaccordance with the 1^(st) parameter and the 2^(nd) color difference issuppressed in accordance with the 2^(nd) parameter, the pseudo-color inthe 1^(st) color difference and 2^(nd) color difference can besuppressed.

In the present invention, the 1^(st) color difference and 2^(nd) colordifference output from the pseudo-color suppression method goes througha low-frequency pass filter to remove high frequency noise resulting incolor difference noise in the color image being decreased and thegeneration of a further enhanced high quality color image.

In the present invention, as the pseudo-color suppression method is toremove high frequency noise from the 1^(st) color difference and 2^(nd)color difference output with a low-frequency pass filter, the phasemismatch between the 1^(st) color difference and 2^(nd) color differencecan be suppressed and a high quality color image obtained.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram expressing the structural composition of animaging device of an embodiment of this invention.

FIG. 2 has explanatory drawings, in the same embodiment, with FIGS. 2(a) and (b) explaining the optical filter pass bandwidth and FIG. 2( c)explaining the resolution for pseudo-color suppression.

FIG. 3 is a diagram explaining, in the same embodiment example, thefunctions of the synchronization unit.

FIG. 4 is an explanatory drawing, in the same embodiment, showing theseeking of the 2^(nd) parameter K2 from the Gr and Gb color difference(Gr−Gb).

FIG. 5 is a flow chart, of the same embodiment, showing the procedurefor an image processing method and an imaging method and an imageprocessing program.

FIG. 6 is a flow chart showing the details of the synchronizationprocedure step in the FIG. 5 flow chart.

FIG. 7 is a flow chart showing the details of the pseudo-colorsuppression step in the FIG. 5 flow chart.

SYMBOL EXPLANATION

1 . . . Imaging Device, 3 . . . Imaging Lens, 5 . . . CCD (ChargeCoupled Devices), 5 a . . . Bayer Array Color Filter, 6 . . . AFE(Analog Front End), 7 . . . CDS, 8 . . . AGC (Automatic Gain Control), 9. . . A/D Conversion Unit 10 . . . Detection Unit, 11 . . . Sensor, 12 .. . Lens Drive Unit, 13 . . . TG (Timing Generator), 21 . . . ColorPlane Decomposition Unit, 22 . . . R Field Memory, 23 a . . . Gr FieldMemory, 23 b . . . Gb Field Memory, 24 . . . B Field Memory, 25 . . .Synchronization Unit, 26 . . . Luminance Y′ Generation Unit, 27 . . .Oblique High Frequency Detection Unit, 28 . . . 1^(st) Color DifferenceGeneration Unit, 29 . . . 2^(nd) Color Difference Generation Unit, 30 .. . Horizontal/Vertical High Frequency Detection Unit, 31 . . .Pseudo-color Suppression Unit, 32 . . . C1 Pseudo-color Removal Unit, 33. . . C2 Pseudo-color Removal Unit, 34 . . . Low-Frequency Pass Filter,37 . . . Color Space Conversion Unit (Color Matrix), 38 . . . CPU(Central Processing Unit), 39 . . . ROM (Read Only Memory), 100 . . .Image Processing Device

BEST EMBODIMENT FOR IMPLEMENTATION OF THE INVENTION 1^(st) Embodiment

Next, we will explain, using the drawings, an embodiment of an imageprocessing device and imaging device, an image processing method and animaging method of this invention.

FIG. 1 is a block diagram showing the configuration of the imagingdevice 1 of the present invention. As shown in FIG. 1, the imagingdevice is comprised of t he digital image signal C (mosaic image signal)of the photographed subject image P from the output of the imagingoptics systems 2 to the CCD 5 and, in accordance with the output digitalsignal C, an image processing device 100 that generates a color imagehaving the plurality of color information of each pixel from the outputof the imaging optics 2.

The image optics system 2 is equipped with such things as an image lens3 which conveys the photographed subject image P to imaging elements 5(CCD: Charged Coupled Devices) that converts the received photographedimage light and outputs an electric amount, an AFE 6 (Analog Front End)which converts the analog image signal output from CCD 5 into a digitalsignal C for output, TG 13 (Timing Generator) which controls the CCD 5and AFE 6 at specific cycles, a lens drive unit 12 that slides theimaging lens 3 in the light axis direction (the Z direction in FIG. 3)and detection unit 10 which detects, via sensor 11, the imaging lens 3slide amount.

CCD 5 is configured with its multiple photo electric conversion elementsarrayed in a matrix condition and each photo electric conversion elementconverts its received image signal photo electrically into an analogimage signal for output.

Also, for the photo electric conversion elements, CCD 5 is equipped witha 3-color R (red), G (green) and B (blue) Bayer array color filter 5 athrough which each color is filtered and the passed through light amountconverted to an electric signal.

AFE 6 is comprised of such things as the CDS 7 (Correlated DoubleSampling) 7 which removes the noise from the CCD 5 output analog imagesignal, AGC 8 which amplifies the correlated double sampling imagesignal from CDS 7, and an A/D Conversion Unit 9 which converts theanalog image signal of CCD 5 (having gone through AGC 8) into a digitalimage signal The image output signal of CCD 5 is converted to thedigital image signal C, at the specified sampling frequency, and outputto the image processing device 100.

Moreover, in the image optics system 2, in addition to CCD 5, CDS 7, AGC8, and A/D Conversion Unit 9, a CMOS (Complementary Metal OxideSemiconductor) sensor may also be used. As the pixel signal output fromCCD 5 only has the single color information of each pixel what is outputfrom the image optics system 2 to the image processing device 100 is theabove noted mosaic image signal.

Next, the image processing device 100 is comprised of such things as thecolor plane decomposition unit 21 which takes the image optics system 2output mosaic image and separates and stores it by each R, Gr, Gb, and Bpixel, a synchronization unit 25 which generates the color informationof the color image pixel position in accordance with the pixel signaloutput from the color plane decomposition unit 21, a pseudo-colorsuppression unit 31 which suppresses the pseudo-color of thesynchronization unit 25 output pixel signal, a low pass filter 34 whichremoves the high frequency component of the pseudo-color suppressionunit 31 output pixel signal, a color space conversion unit (colormatrix) 37 which generates the color information by converting thespecified color space of the image signal after it has gone through thelow pass filter 34, a CPU (Central Processing Unit) 38 and ROM (ReadOnly Memory) 39. The CPU 38, in accordance with the control programstored in ROM 39, o controls each process of the aforementioned imageprocessing device 100 and imaging device 1.

The color plane decomposition unit 21, with the associated Bayer array,is comprised of the R field memory 22 which stores the R pixel signal tomemory, the Gr Field Memory 23 a which stores the Gr (the G next to theR in one direction) pixel signal to memory, the Gb Field Memory 23 bwhich stores the Gb (the G next to the B in one direction) pixel signalto memory, and the B field memory 24 which stores the B pixel signal tomemory. These pixel signals (hereinafter, pixel values) are output tosynchronization unit 25 in accordance with the commands from CPU 38.

The synchronization unit 25, as expressed in FIG. 3, is set beforehandto do such things, for example, as color aberration correction, and foreach of the multiple color planes, calculates, through interpolativeoperation of the same color light pixel value in the color plane, thepixel value at the sampling coordinates 301˜304. Here, the samplingcoordinates 301˜304 is the location on the color mosaic image from thecolor image pixel location associated color space conversion unit (colormatrix) 37.

Also, the synchronization unit 25 is comprised of the luminance Y′generation unit 26 which generates the luminance (Y′) from the sum, withR, Gr, Gb and B as a single unit, of the R, Gr, Gb, B pixel values inaccordance with the each color pixel value found by interpolativecalculation at the color plane decomposition unit 21, the oblique highfrequency detection unit 27 which detects luminance high frequency inthe pixel array oblique direction, the 1^(st) color differencegeneration unit 28 which generates the 1^(st) color difference bysubtracting the R pixel value and B pixel value from the sum of the Grpixel value and Gb pixel value, the 2^(nd) color difference generationunit 29 which generates the 2^(nd) color difference by calculating thedifference between the R pixel value and B pixel value and ahorizontal/vertical high frequency detection unit 30 which detectsluminance high frequency in the horizontal/vertical direction.

In detail, the synchronization unit 25, in accordance with the colormosaic image, calculates the luminance Y′ of each pixel position of theoutput image using the arithmetic expression Y′=(R+Gr+Gb+B)/4,calculates the 1^(st) color difference C1 using the arithmeticexpression C1=(Gr+Gb−R−B)/4, calculates the 2^(nd) color difference C2using the arithmetic expression (R−B)/2 and calculates the 2^(nd)parameter K2 using the arithmetic expression (Gr−Gb)/2.

Here, as expressed in FIG. 4( a)(b), if pseudo-color occurs in the2^(nd) color difference C2 (in the Figure, pseudo-color is indicated byhatching), it can be thought that pseudo-color also occurs for the Gr toGb color difference (Gr−Gb) so, the 2^(nd) parameter K2 can be soughtusing the above noted arithmetic expression.

Also, as regards parameter K1, a filter having a weighting factor(Formula 1) is applied to the color mosaic image and, after filterapplication, using the color plane of the color mosaic image the R and Binterpolative value, as expressed in FIG. 3, is sought and using the Rinterpolative value and B interpolative value the value of K1 is foundusing the arithmetic expression K1=(R−B)/2.

$\begin{matrix}{{Formula}\mspace{14mu} 1} & \; \\{\begin{pmatrix}1 & 0 & {- 2} & 0 & 1 \\0 & 0 & 0 & 0 & 0 \\{- 2} & 0 & 4 & 0 & {- 2} \\0 & 0 & 0 & 0 & 0 \\1 & 0 & {- 2} & 0 & 1\end{pmatrix}/16} & \left\lbrack {{No}.\mspace{14mu} 1} \right\rbrack\end{matrix}$

Also, when the output image pixel position is associated with each pixelposition of the color mosaic image, by applying a filter to the colormosaic image the luminance (Y′), 1^(st) color difference C1, 2^(nd)color difference C2 and 2^(nd) parameter K2 can be obtained and byapplying a filter (Formula 2) to the 1^(st) color difference C1 the1^(st) parameter K1 can also be obtained.

$\begin{matrix}{{Formula}\mspace{14mu} 2} & \; \\{\begin{pmatrix}1 & {- 2} & 1 \\{- 2} & 4 & {- 2} \\1 & {- 2} & 1\end{pmatrix}/16} & \left\lbrack {{No}.\mspace{14mu} 2} \right\rbrack\end{matrix}$

As noted above, the 1^(st) parameter K1 is the indicator expressing thepixel value change amount in the oblique direction having the pixel asits center, but it is not necessarily limited to (R−B), any pixel arraywith 45° interlacing in the oblique direction to the stripe pattern isacceptable. Also, at this time, if the image is one that does not haveany change, K1 does not have a value even if the image has color so itis desirable that it does not have any value on the stripe pattern evenin the horizontal/vertical direction and, furthermore, the filter shouldbe comprised such that the high frequency 45° oblique direction stripepattern value be a large value.

Next, such things as the luminance Y′ generated by the luminancegeneration unit 26 is output to the color space conversion unit (colormatrix) 37, the 1^(st) parameter K1 detected by the oblique highfrequency detection unit 27, the 1^(st) color difference C1 generated bythe 1^(st) color generation unit 28, the 2^(nd) color difference C2generated by the 2^(nd) color generation unit 29, and the 2^(nd)parameter K2 detected by the horizontal/vertical high frequencydetection unit 30 are output to the pseudo-color suppression unit 31.Moreover, the function of the synchronization method and thepseudo-color information generation method of the present invention isexpressed by the synchronization unit 25.

The pseudo-color suppression unit 31 is comprised of the C1 pseudo-colorremoval unit 32 which suppresses the 1^(st) color difference C1pseudo-color in accordance with the 1^(st) parameter K1 and 1^(st) colordifference C1 input from the synchronization unit 25 and the C2pseudo-color removal unit 33 which suppresses the 2^(nd) colordifference C2 pseudo-color in accordance with the 2^(nd) parameter K2and 2^(nd) color difference C2.

The C1 pseudo-color color removal unit 32 suppresses the 1^(st) colordifference amount C1 generated by the synchronization unit 25 inaccordance with the 1^(st) parameter K1 and the C2 pseudo-color colorremoval unit 33 suppresses the 2^(nd) color difference amount C2generated by the synchronization unit 25 in accordance with the 2^(nd)parameter K2.

For example, using the formulas below, using the C1, C2 absolute values(as long as they do not bridge 0), all that needs to be done is tosubtract the value obtained by multiplying the K1, K2 absolute values bythe m1, m2 coefficients.

C1→sign(C1)*max((0, abs (C1)−m1*abs(K1))

C2→sign(C2)*max((0, abs (C2)−m2*abs(K2))

Here, m1, m2 are parameters for adjustment of pseudo-color suppressionstrength. The function of the pseudo-color suppression method of thepresent invention is expressed by the pseudo-color suppression unit 31.

Next, the low frequency pass filter 34 is comprised of the 1^(st) lowfrequency pass filter 35 which further suppresses the pseudo-color ofthe 1^(st) color difference C1 as output from the C1 pseudo-color colorremoval unit 32 and the 2^(nd) low frequency pass filter 36 whichfurther suppresses the pseudo-color of the 2^(nd) color difference C2 asoutput from the C2 pseudo-color color removal unit 33.

As expressed in FIG. 2( c), the luminance Y′ 1^(st) color difference C1and 2^(nd) color difference C2 from synchronization unit 25 each havediffering resolution boundaries with the C1 pass width being greaterthan the pass width of C2. Therefore, by using a LPF (low pass filter)for C1 that has a greater pass width than that of the one for C2,resolution deterioration can be lessened and effective pseudo-colorsuppression obtained.

For example, all that needs to be done is to apply a filter (Formula 3)to C1 and a filter (Formula 4) to C2.

$\begin{matrix}{{Formula}\mspace{14mu} 3} & \; \\{\begin{pmatrix}0 & 1 & 0 \\1 & 0 & 1 \\0 & 1 & 0\end{pmatrix}/4} & \left\lbrack {{No}.\mspace{14mu} 3} \right\rbrack \\{{Formula}\mspace{14mu} 4} & \; \\{\begin{pmatrix}1 & 0 & 1 \\0 & 0 & 0 \\1 & 0 & 1\end{pmatrix}/4} & \;\end{matrix}$

Or, by using a LPF for C1 that has a narrower pass width than that of C2the frequency characteristics of C1 and C2 are aligned and an imagewithout any unnaturalness can be made.

For example, one can apply a filter (Formula 5) to C1 and then apply thefilter (Formula 6) to C2.

$\begin{matrix}{{Formula}\mspace{14mu} 5} & \; \\{\begin{pmatrix}1 & 2 & 1 \\2 & 4 & 2 \\1 & 2 & 1\end{pmatrix}/16} & \left\lbrack {{No}.\mspace{14mu} 4} \right\rbrack \\{{Formula}\mspace{14mu} 6} & \; \\{\begin{pmatrix}0 & 1 & 0 \\1 & 4 & 1 \\0 & 1 & 0\end{pmatrix}/8} & \;\end{matrix}$

Subsequently, the color space conversion unit (color matrix) 37 convertsthe luminance Y′ from the synchronization unit 25, the 1^(st) colordifference C1 and the 2^(nd) color difference C2 from the pseudo-colorsuppression unit 31 into a standard color image predetermined colorspace to generate YUV color information (Y=luminance, U and V are colorinformation).

For example, the R pixel value component is sought in the R=Y′−C1+C2arithmetic expression, the G pixel value component is sought in theG=Y′+C1 arithmetic expression and the B pixel value component is soughtin the B=Y′−C1−C2 arithmetic expression. Furthermore, using Formula 7,just convert the RGB to YUV color information.

$\begin{matrix}{{Formula}\mspace{14mu} 7} & \; \\{\begin{pmatrix}Y \\U \\V\end{pmatrix} = {\begin{pmatrix}0.299 & 0.587 & 0.114 \\{- 0.147} & {- 0.289} & 0.436 \\0.615 & {- 0.515} & {- 0.100}\end{pmatrix}{\begin{pmatrix}R \\G \\B\end{pmatrix}.}}} & \left\lbrack {{No}.\mspace{14mu} 5} \right\rbrack\end{matrix}$

Then, as in the above, for all the pixels in the color image, processingby the image processing device 100 is conducted and the YUV colorinformation is output to the visual correction unit (not indicated inthe drawings) in which known art image correction processes such asgamma correction, color saturation correction or edge emphasis areconducted.

2^(nd) Embodiment

In the 1^(st) embodiment, the pseudo-color of the 1^(st) colordifference C1 and 2^(nd) color difference C2 was suppressed in thepseudo-color suppression unit 31 and then further suppressed by beingsent through the low frequency pass filter 34. However, in the 2^(nd)embodiment, the suppression of the 1^(st) color difference C1pseudo-color in the pseudo-color suppression unit 31 and the lowfrequency pass filter 34 is dropped and only the 2^(nd) color differenceC2 pseudo-color is suppressed. Also, as the basic composition of theimaging device 1 is common with that of the 1^(st) embodiment, followingbelow are details regarding only the distinguishing parts.

The 2^(nd) embodiment imaging device 1 is equipped with an optical lowpass filter (not indicated in the drawing) for removal of unwantedfrequency space between the imaging lens 3 and CCD 5. The color mosaicimage pixel signal from the image optics system 2 goes through the colorplane decomposition unit 21 and is input to the synchronization unit 25.

The cutoff of the above noted optical low pass filter, as expressed inFIG. 2( a), (b), is associated with the pixel array direction of thelater noted color mosaic image forming a quadrangle having a 45° obliqueangle with the origin point as its center on the above mentioned colormosaic image frequency space, with the inside of this quadrangle beingthe transmission band. In detail, the optical low pass filter is a 4point separate type, with the opposing point pixel pitch so as to becomean even 1/fs, the light rays are separated to the 4 apexes of a squareand the luminance high frequency, which is the origin of G (green) andviolet pseudo-color, can be effective suppressed.

The synchronization unit 25, as expressed in FIG. 3, for each of themultiple color planes, calculates, through interpolative operation ofthe same color light pixel value in the color plane, the pixel value atthe sampling coordinates 301˜304.

Next, the synchronization unit 25, in accordance with the color mosaicimage, calculates the luminance Y′ of each pixel position of the outputimage using the arithmetic expression Y′=(R+Gr+Gb+B)/4, calculates the1^(st) color difference C1 using the arithmetic expressionC1=(Gr+Gb−R−B)/4, calculates the 2^(nd) color difference C2 using thearithmetic expression (R−B)/2 and calculates the 2^(nd) parameter K2using the arithmetic expression (Gr−Gb)/2.

Also, when the output image pixel position is associated with each pixelposition of the color mosaic image, by applying a filter (Formula 8)through (Formula 11) to the color mosaic image the luminance (Y′),1^(st) color difference C1, 2^(nd) color difference C2 and 2^(nd)parameter K2 can be sought.

In detail, by applying the filter (Formula 8) to the color mosaic imageformed from the R, Gr, Gb, B, the luminance Y′ can be obtained.

$\begin{matrix}{{Formula}\mspace{14mu} 8} & \; \\{\begin{pmatrix}1 & 2 & 1 \\2 & 4 & 2 \\1 & 2 & 1\end{pmatrix}/16} & \left\lbrack {{No}.\mspace{14mu} 6} \right\rbrack\end{matrix}$

Also, in the color mosaic image, the 1^(st) color difference C1 valuecan be obtained by totaling the sums from the filtered output of the Grand Gb pixels (Formula 9) and the R and B pixels.

$\begin{matrix}{{Formula}\mspace{14mu} 9} & \; \\{\begin{pmatrix}1 & {- 2} & 1 \\{- 2} & 4 & {- 2} \\1 & {- 2} & 1\end{pmatrix}/16} & \left\lbrack {{No}.\mspace{14mu} 7} \right\rbrack \\{{Formula}\mspace{14mu} 10} & \; \\{\begin{pmatrix}{- 1} & 2 & {- 1} \\2 & {- 4} & 2 \\{- 1} & 2 & {- 1}\end{pmatrix}/16} & \;\end{matrix}$

Also, in the color mosaic image, the 2^(nd) color difference C2 valuecan be obtained by totaling the sums from the filtered output of the Rpixels (Formula 11), the B pixels (Formula 12), the Gr pixels (Formula13) and the Gb pixels (Formula 14).

$\begin{matrix}{{Formula}\mspace{14mu} 11} & \; \\{\begin{pmatrix}{- 1} & 0 & {- 1} \\0 & 4 & 0 \\{- 1} & 0 & {- 1}\end{pmatrix}/8} & \left\lbrack {{No}.\mspace{14mu} 8} \right\rbrack \\{{Formula}\mspace{14mu} 12} & \; \\{\begin{pmatrix}1 & 0 & 1 \\0 & {- 4} & 0 \\1 & 0 & 1\end{pmatrix}/8} & \; \\{{Formula}\mspace{14mu} 13} & \; \\{\begin{pmatrix}0 & {- 2} & 0 \\2 & 0 & 2 \\0 & {- 2} & 0\end{pmatrix}/16} & \; \\{{Formula}\mspace{14mu} 14} & \; \\{\begin{pmatrix}0 & 2 & 0 \\{- 2} & 0 & {- 2} \\0 & 2 & 0\end{pmatrix}/16} & \;\end{matrix}$

Also, in the color mosaic image, the 2^(nd) parameter K2 value can beobtained by totaling the sums from the filtered output of the Gr pixels(Formula 15), the Gb pixels (Formula 16), the R pixels (Formula 17) andthe B pixels (Formula 18).

$\begin{matrix}{{Formula}\mspace{14mu} 15} & \; \\{\begin{pmatrix}{- 1} & 0 & {- 1} \\0 & 4 & 0 \\{- 1} & 0 & {- 1}\end{pmatrix}/8} & \left\lbrack {{No}.\mspace{14mu} 9} \right\rbrack \\{{Formula}\mspace{14mu} 16} & \; \\{\begin{pmatrix}1 & 0 & 1 \\0 & {- 4} & 0 \\1 & 0 & 1\end{pmatrix}/8} & \; \\{{Formula}\mspace{14mu} 17} & \; \\{\begin{pmatrix}0 & {- 2} & 0 \\2 & 0 & 2 \\0 & {- 2} & 0\end{pmatrix}/16} & \; \\{{Formula}\mspace{14mu} 18} & \; \\{\begin{pmatrix}0 & 2 & 0 \\{- 2} & 0 & {- 2} \\0 & 2 & 0\end{pmatrix}/16} & \;\end{matrix}$

As noted above, the 2^(nd) parameter K2 is the indicator expressing thepixel value change amount in the oblique direction having the pixel asits center, but it is not necessarily limited to (Gr−Gb), any pixelarray with 45° interlacing in the oblique direction to the stripepattern is acceptable. Also, at this time, if the image is one that doesnot have any change, K2 does not have a value even if the image hascolor so it is desirable that it does not have any value on the stripepattern even in the horizontal/vertical direction and, furthermore, thefilter should be comprised such that the cycle 2/fs horizontal/verticaldirection stripe pattern value be a large value.

Next, the luminance Y′ generated by the luminance Y′ generation unit 26and the 1^(st) color difference C1 generated by the 1^(st) colordifference generation unit 28 is output to the color space conversionunit (color matrix) 37 and the 2^(nd) color difference C2 generated bythe 2^(nd) color generation unit 29, and the 2^(nd) parameter K2expressing the high frequency component detected by thehorizontal/vertical high frequency detection unit 30 are output to thepseudo-color suppression unit 31.

Next, the pseudo-color suppression unit 31 suppresses the 2^(nd) colordifference in accordance with the 2^(nd) parameter K2 and 2^(nd) colordifference as input from the synchronization unit 25.

In other words, in the C2 pseudo-color color removal unit 33, the 2^(nd)color difference C2 amount generated at the synchronization unit 25 issuppressed in accordance with the 2^(nd) parameter K2.

For example, using the formula below, all that needs to be done is tosubtract the K2 absolute value from the C2 absolute value (as long as itdoesn't bridge 0).

C2→sign(C2)*max((0, abs(C2)−ml*abs(K2))

Here, m1 is the parameter for adjustment of pseudo-color suppressionstrength.

Subsequently, the color space conversion unit (color matrix) 37 convertsthe luminance Y′ from the synchronization unit 25, the 1^(st) colordifference C1 and the 2^(nd) color difference C2 from the pseudo-colorsuppression unit 31 into a standard color image predetermined colorspace.

For example, for RGB color space conversion all that needs to be done isseek the R pixel value component with the R=Y′−C1+C2 arithmeticexpression, the G pixel value component with the G=Y′+C1 arithmeticexpression and the B pixel value component with the B=Y′−C1−C2arithmetic expression. Subsequently, the RGB color information obtainedfrom the color space conversion unit (color matrix) 37 is output to thevisual correction unit (not indicated in the drawings) in which knownart image correction processes such as gamma correction, colorsaturation correction or edge emphasis are conducted.

3^(rd) Embodiment

Next, using FIG. 5 to FIG. 7 we will explain the image processing methodand image processing program procedure of an embodiment of thisinvention. This procedure, following the program stored to ROM 39 by CPU38, executes the provision of the command signals to each function unit.Please note, the letter ‘S’ in FIG. 5 to FIG. 7 is an abbreviation ofStep.

This image processing method and image processing program is applied tothe image processing device 100 expressed in the 1^(st) embodiment and2^(nd) embodiment.

First, this procedure begins when, through the operator, the startsignal is input to the imaging device 1 or the image processing device100.

Next, in S100, the image signal from the image optics system 2 is readin by the image processing device 100, Bayer array mapping is done atthe color plane decomposition unit 21 and the R pixel signal, Gr pixelsignal, Gb pixel signal and B pixel signal are recorded and then aresent to the S200 synchronization step.

In S200 as expressed in FIG. 6, first the sampling coordinates areobtained at S210 and then transferred to S220. At this time the samplingcoordinates have the corresponding color image pixel position and theyare preliminarily stored to ROM 39.

In S220, for each of the plurality of color planes, the pixel value inthe sampling coordinates is calculated by interpolation from the samelight color pixel value within the color plane and then goes to S230.

In S230, in accordance with each color pixel value sought byinterpolation, with R, Gr, Gb and B as a single unit, a luminance (Y′)is generated from the sum of the pixel signals R, Gr, Gb and then goesto S240. The function of the luminance generation step of the presentinvention is expressed by S230.

In S240, by subtracting the above mentioned R pixel signal and B pixelsignal from the sum of the Gr pixel signal and Gb pixel signal a 1^(st)to color difference C1 is generated and, at the same time, thedifference between the R pixel signal and B pixel signal is calculatedto generate a 2^(nd) color difference C2 and then sent to S250. Thefunction of 1^(st) color difference generation step and 2^(nd) colordifference generation step of the present invention is expressed byS240.

In 250, along the pixel array the luminance high frequency expressed inthe oblique direction K1 and the luminance high frequency expressed inthe horizontal/vertical direction K2 is detected and then sent to theS300 pseudo-color suppression step of FIG. 5. The function of thepseudo-color generation step of the present invention is expressed byS250.

In S300, as expressed in FIG. 7, first the pseudo-color suppression modeis selected in S310. The pseudo-color suppression mode is pre-determinedwith Mode 1 being both the 1^(st) color difference C1 and 2^(nd) colordifference C2 pseudo-color suppression, Mode 2 being the 1^(st) colordifference C1 pseudo-color suppression and Mode 3 being the 2^(nd) colordifference C2 pseudo-color suppression. Also, the selection of Modes 1˜3is executed in accordance with command signal from the operator.

In S310, when Mode 1 is selected, as noted in the 1^(st) embodiment,upon transfer to S320 the 1^(st) parameter K1 and the 2^(nd) parameterK2 are obtained and then, in S330, the 1^(st) color difference C1 and2^(nd) color difference C2 pseudo-color suppression is performed.

Alternatively, in S310, when Mode 2 is selected, upon transfer to S340the 1^(st) parameter K1 is obtained and then, in S350 the 1^(st) colordifference C1 pseudo-color suppression is performed. At this time, asnoted in the 1^(st) embodiment, the 1^(st) color difference C1pseudo-color suppression is performed.

Alternatively, in S310, when Mode 3 is selected, upon transfer to S360,as noted in the 2^(nd) embodiment, the 2^(nd) parameter K2 is sought andthen, after transfer to S370 the 2^(nd) color difference C2 pseudo-colorsuppression is performed. The function of the pseudo-color suppressionstep of the present invention is expressed by S310˜S370.

Next, upon transfer to S400 of FIG. 5, a low-frequency pass filter 34 isused on the 1^(st) color difference C1 and 2^(nd) color difference C2 toremove the high frequency constituent and then transferred to S500.

In S500, luminance Y′, pseudo-color suppressed 1^(st) color differenceC1 and 2^(nd) color difference C2 are converted to a standard colorimage color space and the YUV color information of each pixel of thecolor image is generated and then transferred to S600.

In S600, a sampling determination is made and if sampling has not beendone (No) the image processing program finishes and if sampling has beendone (Yes) S200˜S600 process is repeated over again and when no samplingis reached the image processing program finishes.

As in this embodiment noted above, it is possible to use an imageprocessing device 100, an imaging device 1, an image processing methodand an imaging method, and an image processing program which caneffectively suppress pseudo-color without degrading the resolution andgenerate a high quality color image wherein: the R, Gr, Gb and B pixelsignals are unified into a single unit by correlating them with pixelpositions in a color image, a luminance (Y′) is generated from the sumof the pixel signals R, Gr, Gb, and B, then the R pixel signal and the Bpixel signal is subtracted from the sum of the Gr pixel signal and Gbpixel signal so as to generate a 1^(st) color difference C1, and at thesame time the difference between the R pixel signal and the B pixelsignal is calculated to generate a 2^(nd) color difference C2. Next, apseudo-color suppression unit performs pseudo-color suppression of toboth the 1^(st) color difference C1 and the 2^(nd) color difference C2.Subsequently, a color space conversion unit converts the pseudo-coloredsuppressed 1^(st) color difference C1 and 2^(nd) color difference C2into a predetermined color space to generate the color information.

In this embodiment, in the synchronization unit 25, by generation of the1^(st) parameter K1 and 2^(nd) parameter K2 expressing the highfrequency component amount in the oblique and horizontal/verticaldirections the luminance of the 1^(st) color difference C1 and 2^(nd)color difference C2 included in the pseudo-color signal can be well andprecisely suppressed.

In this embodiment, as the 2^(nd) parameter K2 is the marker expressingthe difference between the Gr pixel signal and the Gb pixel signal, thepseudo-color amount is calculated in accordance with the differencebetween Gr and Gb and pseudo-color can be suppressed.

In this embodiment, in the pseudo-color suppression unit 31, inaccordance with the 1^(st) parameter K1 and 1^(st) color difference C1,the pseudo-color included in the 1^(st) color difference C1 issuppressed and in accordance with the 2^(nd) parameter K2 and 2^(nd)color difference C2, the pseudo-color included in the 2^(nd) colordifference C2 can be suppressed.

In this embodiment, the output of the 1^(st) color difference C1 and2^(nd) color difference C2 from the pseudo-color suppression unit 31,goes through the low-frequency pass filter 34 to remove high frequencynoise and color difference noise in the color image can be decreasedresulting in the obtaining of a further enhanced high quality image.

In the image processing program of this embodiment, as expressed inS310, a plurality of modes can be selected when suppressing pseudo-colorand improvement of user-friendliness and convenience can be obtained.

As above we have explained one embodiment of this invention but thisinvention is not limited to just the above mentioned embodiment and itcan take many different aspects.

For example, in S300, pseudo-color is suppressed and then, in S400 thelow pass filtering (LPF) 34 is performed but it is also possible to dothe low-pass filter process S400 before performing the S300 pseudo-colorsuppression. When so doing, it is preferred that the oblique highfrequency and horizontal/vertical high frequency luminance detected bysynchronization unit 25 also go through the low-pass filter process.

INDUSTRIAL APPLICABILITY

The 1^(st) color difference and 2^(nd) color difference are generatedfrom the color mosaic image and it is possible to obtain a color imagefrom them after a specified quantitative change.

1. Image processing device for generating a color image having a plurality of color information for each pixel from a color mosaic image obtained from a Bayer array filter equipped CCD with R (red) Gr (the green next to the above mentioned R in one direction of the pixel array), Gb (the green next to the B in the above mentioned one direction) and B (blue) pixels and, wherein, at the pixel position in the above mentioned color image with the above mentioned R, Gr, Gb and B pixels as a single unified unit, a luminance (Y) is generated from the sum of the above mentioned R, Gr Gb and B pixel signals and a 1^(st) color difference is generated by subtracting the above mentioned R pixel signal and B pixel signal from the sum of the above mentioned Gr pixel signal and Gb pixel signal and the image processing device comprising a synchronization facility for generating a 2^(nd) color difference by calculating the difference between the above mentioned R pixel signal and B pixel signal and, the image processing device comprising a pseudo-color suppression facility for suppressing pseudo-color in at least one of the above mentioned 1^(st) color difference and 2^(nd) color difference, a color space conversion facility for converting the pseudo-color suppressed 1^(st) color difference and 2^(nd) color difference obtained from the pseudo-color suppression facility using said luminance into a determined color space and for generating the above mentioned color information.
 2. Image processing device of claim 1, provided with a pseudo-color information generation facility, that generates at least one of a 1^(st) parameter or 2^(nd) parameter expressing the high frequency component amount of a luminance in mutually differing directions.
 3. Image processing device of claim 2 wherein the above mentioned 2^(nd) parameter is a parameter that expresses a difference between the above mentioned Gr pixel signal and the Gb pixel signal.
 4. Image processing device of claim 2 wherein the above mentioned pseudo-color suppression facility is arranged to suppress the above mentioned 1^(st) color difference in accordance with the above mentioned 1^(st) parameter and is arranged to suppress the above mentioned 2^(nd) color difference in accordance with the above mentioned 2^(nd) parameter.
 5. Image processing device of claim 1 further according to having a low frequency pass filter for removal of the high frequency component in the 1^(St) color difference and 2^(nd) color difference obtained from the above mentioned pseudo-color suppression facility.
 6. Image processing device of claim 1 wherein the above mentioned pseudo-color suppression facility is a low frequency pass filter for removal of the high frequency component of the 1^(st) color difference and 2^(nd) color difference.
 7. Imaging device comprising an image processing device according to claim 1 further comprising an imaging optics system to image an object image to the CCD and wherein the above mentioned image processing device generates a color image having the multiple color information of each pixel in accordance with the mosaic image signal output from the above mentioned CCD.
 8. Imaging device of claim 7 being equipped with an optical low-pass filter for suppression of luminance high frequency of an oblique direction on the above mentioned color image pixel array, the optical low-pass filter being arranged in the incident light path forming the object image on the above mentioned CCD, the cutoff of the aforementioned optical low pass filter being associated with the above mentioned color mosaic image pixel array direction, forming a quadrangle having a 45° angle in the above mentioned color mosaic image frequency space and with the origin point of said space as its center, with the inside of this quadrangle being the transmission band.
 9. Image processing method for generating a color image having a plurality of color information for each pixel from a color mosaic image from a Bayer array filter equipped CCD with R (red), Gr (the green next to the above mentioned R in one direction of the pixel array), Gb (the green next to the B in the above mentioned one direction) and B (blue) pixels and said method comprising, at the pixel position in the above mentioned color image with the above mentioned R, Gr, Gb and B pixels as a single unified unit, a luminance generation step for generating a luminance (Y) from the sum of the above mentioned R, Gr, Gb and B pixel signals and, a 1^(st) color difference generation step for generating a first color difference wherein the above mentioned R pixel signal and B pixel signal are subtracted from the sum of the above mentioned Gr pixel signal and Gb pixel signal and, a 2^(nd) color difference generation step for generating a second color difference wherein the difference between the above mentioned R pixel signal and B pixel signal is calculated and, a pseudo-color suppression step for suppressing pseudo-color in at least one of the above mentioned 1^(st) color difference and 2^(nd) color difference and, a color space conversion step for converting said 1^(st) color difference and 2^(nd) color difference for which said pseudo-color step using said luminance was applied into a predetermined color space and for generating the above mentioned color information.
 10. Image processing method according to claim 9 comprising a pseudo-color information generation step involving generation of at least one parameter of a 1^(st) or a 2^(nd) parameter expressing the high frequency component amount of the luminance in mutually differing directions pseudo-color suppression information for said pseudo-color suppression step.
 11. mage processing method according to claim 10 wherein said 2^(nd) parameter is a parameter expressing a difference between the above mentioned Gr pixel signal and Gb pixel signal.
 12. Image processing method according to claim 10 wherein in said pseudo-color suppression step, the above mentioned 1^(st) color difference pseudo-color is suppressed in accordance with the above mentioned 1^(st) parameter and the above mentioned 2^(nd) color difference pseudo-color is suppressed in accordance with the above mentioned 2^(nd) parameter.
 13. Image processing method according claim 9 wherein a low pass filter is used to remove a high frequency component from the pseudo color suppressed 1^(st) color difference and 2^(nd) color difference obtained from the above mentioned pseudo-color suppression step.
 14. Image processing method according to claim 9 wherein in said pseudo-color suppression step the 1^(st) color difference and 2^(nd) color difference high frequency component is removed with the use of a low frequency pass filter.
 15. Imaging method comprising the said image processing method according to claim 9 wherein a color image having a plurality of color information for each pixel is generated in accordance with the image signal of the color mosaic image output, which uses a photo-optical system to introduce the image, from the above mentioned CCD.
 16. Imaging processing method according to claim 15 wherein in the incident light path forming the object image on the above mentioned CCD, the above mentioned color image pixel array is equipped with an optical low pass filter for suppression of high frequency luminance in an oblique direction with the cutoff of the aforementioned optical low pass filter being associated with the above mentioned color mosaic image pixel array direction, forming a quadrangle having a 45° angle in said color mosaic image frequency space with the origin point of said space as its center on, with the inside of this quadrangle being the transmission band.
 17. Image processing program for computer execution wherein: a color image having a plurality of color information for each pixel from a color mosaic image obtained from a Bayer array filter equipped CCD with R (red) Gr (the green next to the above mentioned R in one direction of the pixel array), Gb (the green next to the B in the above mentioned one direction) and B (blue) pixels is generated and at the pixel position in the above mentioned color image with the above mentioned R, Gr, Gb and B pixels being a single unified unit, the program comprising a luminance generation step (Y) for generating a luminance from the sum of the above mentioned R, Gr Gb and B pixel signals and, comprising a 1^(st) color difference generation step for generating a first color difference, by subtracting the above mentioned R pixel signal and B pixel signal from the sum of the above mentioned Gr pixel signal and Gb pixel signal and, a 2^(nd) color difference generation step for generating a 2^(nd) color difference, by calculation of the difference between the above mentioned R pixel signal and B pixel signal and, a pseudo-color suppression step for suppressing pseudo-color in at least one of said 1^(st) color difference and said 2^(nd) color difference, a color space conversion step for converting the pseudo-color suppressed 1^(st) color difference and 2^(nd) color difference, having gone through the above-mentioned pseudo-color suppression steps using said luminance, into a determined color space and for generating the above mentioned color information.
 18. Image processing program according to claim 17 that causes a computer to perform a pseudo-color information generation step that generates as the said pseudo-color suppression information at least one parameter of the 1^(st) or 2^(nd) parameter expressing the high frequency component amount of the luminance in mutually different directions.
 19. Image processing program according to claim 18 wherein the above mentioned 2^(nd) parameter is the parameter expressing the difference between the above mentioned Gr pixel signal and the above mentioned Gb pixel signal.
 20. Image processing program according to claim 18, wherein, in the above mentioned pseudo-color suppression, the pseudo-color of the above mentioned 1^(st) color difference is suppressed in accordance with the above mentioned 1^(st) parameter and the pseudo-color of the 2^(nd) color difference is suppressed in accordance with the above mentioned 2^(nd) parameter by execution of the computer program. 21.-22. (canceled) 